Methyl-substituted polyphenylcarboxylic acids

ABSTRACT

Methyl-substituted polyphenylacyl compounds are prepared by selective oxidation of oligomers of mesitylene. These methyl-substituted polyphenylacyl compounds are useful as intermediates for polyamides and polyesters. The esters are useful as plasticizers for polyvinylchloride.

This is a division of application Ser. No. 622,656, filed Oct. 15, 1975,now U.S. Pat. No. 4,154,922 which is a continuation-in-part of Ser. No.517,506 filed Oct. 24, 1974, now abandoned.

BACKGROUND OF THE INVENTION

The field of this invention relates to aromatic polyacyl compounds ofpolyphenyl structure suitable for polymers useful for forming shapedobjects, such as film, fiber and molded parts. The esters are suitableas plasticizers for polyvinylchloride and other polymers.

As is well known, the mechanical and physical properties of a fiber orfilm depend on the chemical structure of the polymer from which they aremade. For example, the melting point, molding temperature, and glasstransition temperature of the polymer composition control many of thephysical properties and fabrication of the shaped objects. The meltingpoint determines thermal resistance and heat-setting temperature offibers. Molding temperature determines fabrication temperature. Glasstransition temperature (Tg) determines initial modulus, tensile strainrecovery, work of recovery, drape and hand, wash-and-wearcharacteristics, comfort factors and resilience of fibers. The mainmolecular factors which influence these properties include chainstiffness, the intermolecular forces, orientation and crystallinity.

Accordingly, there has been considerable interest in developing aromaticsymmetrical acids as precursors for thermally stable polymers, such aspolyesters or polyamides. It is well known that the introduction ofaromatic units in the polymer chain backbone results in high bondenergies, a low degree of reactivity, and rigidity of the polymer chainstructure. The use of aliphatic units in the polymer chain backboneresults in flexibility, lower temperature characteristics and decreasedstrength as compared with the aromatic types.

Substantially all commercial polyester fibers are based on terephthalicacid. While these fibers have many excellent properties there is a needfor polyester fibers having a higher Tg than provided by terephthalicacid polyesters. Recently, 2,6-naphthalene dicarboxylic acid has beenproposed as a suitable aromatic acid for producing polyesters suitablefor tire cord. This acid provides polyesters having a higher Tg thanthose based on terephthalic acid. For example, poly(ethyleneterephthalate) has a Tg of 74° C. while poly(ethylene 2,6-naphthalate)has a Tg of 115°-125° C. However, the difficulties of manufacturing theprecursor, i.e., 2,6-dimethylnaphthalene, have made the production ofthis acid technically difficult and economically costly. The acid canrequire a four-step synthesis with attendant loss in yield andconsequent high cost.

Various other organic polymers have been suggested for use as hightemperature fibers, such as copolyamides (Kevlar), polybenzimidazoles,polyoxadiazoles, polyimides and phenylene ring systems (polyphenylenes).Polyarylates and polycarbonates have been suggested for use asengineering plastics. However, all of these are costly and/or difficultto manufacture. Accordingly, there is a need for new aromatic acidssuitable for preparing polymers for many uses.

It is the object of this invention to provide a new group of aromaticpolycarboxylic acids of polyphenyl structure which will meet this need.Another object of this invention is to provide a process for makingthese acids. Another object of this invention is to provide a newpolycarboxylic acid, specifically 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid, for use in polymer chains. Afurther object is to provide novel polymers, both polyamides andpolyesters, made from these acids. Other and further objects of thisinvention will be apparent from the following description.

The field of this invention, accordingly, has three aspects. First itrelates to novel compositions of matter which are methyl-substitutedpolyphenylacyl compounds and to the method of preparing these acylcompounds. Second, it relates to novel polyamides based onmethyl-substituted polyphenylacyl compounds. Third, it relates to novelpolyesters based on these same novel acyl compounds.

These novel methyl-substituted polyphenylacyl compounds (acids, acylhalides, simple esters, e.g., methyl, etc.) are desirable intermediatesfor producing condensation polymers, such as polyamides and polyesterssuitable for shaped articles such as film, fiber and molded parts. Theesters of these acids and monohydric alcohols containing 4 to 24 carbonatoms can be used as plasticizers for polyvinylchloride (PVC).

The abstract of an article by Y. Nomura and Y. Takeuchi (J. Chem. Soc.(B) 1970, 956-960) mentions the structure2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid and its methylester but no further references to the compounds or to their propertiesor preparation are given in the abstract or in the article. There is noindication that these compounds were made nor suggestion how to makethese compounds. Low yields of other substituted biphenyls are reportedby the authors. For example, 4.8 grams of4,4'-diamino-2,2',6,6'-tetramethylbiphenyl were prepared in 52% yieldfrom 3,5-dimethylnitrobenzene which in turn yielded only 0.10 grams of4,4'-dicyano-2,2',6,6'-tetramethylbiphenyl in 2% yield, and an overallyield of only 1% to the dicyano compound.

It has been found, in accordance with this invention, that the paracarboxylic acid polyphenyls may be prepared in a very convenient mannerby the oxidation of the para methyl groups of the methyl-substitutedpolyphenyls, e.g., bimesityl, by means of molecular oxygen in thepresence of a cobalt compound, as for example; cobaltic acetate, and theprocess is especially convenient and advantageous if carried out in thepresence of acetic acid. Ortho-methyl groups, the 2 and 6 methylsubstituents of the polyphenyls, were found to require more severeoxidizing conditions; thus the pentacarboxylic biphenyl was found torequire more severe oxidative conditions with the utilization ofmolecular oxygen in the presence of cobalt and manganese acetate, aceticacid, sodium bromide, and tetrabromomethane.

It has been found also that the novel polyesters prepared from themethyl-substituted diphenylcarboxylic acids and dihydric alcohols, suchas those having two to ten carbon atoms unexpectedly possess high secondorder transition temperatures (Tg), transparency, colorlessness andtoughness. These novel polyesters can be made into tough films andfibers. Molding temperature of the ethylene glycol polyester isunexpectedly low, with resultant savings in fabrication heat input.Density of the ethylene glycol polyester is 15 to 20% less than thedensity of poly(ethylene terephthalate), with resultant weight advantageover PET. The limiting oxygen index (LOI) of the ethylene glycolpolyester of this invention is approximately 5% more than that of PETwith resultant improved non-burning characteristics.

In recent years a limited amount of work has been done involvingp,p'-bibenzoic acid and its esters in connection with homopolyesters.U.S. Pat. No. 3,008,929, for example, indicates that this work was notgenerally fruitful, for a homopolyester of bibenzoic acid and a glycol(e.g., polyethylenebibenzoate) possesses an extremely high melting pointmaking its use in shaped articles entirely impractical, particularlywhen attempts are made to use it as a film or fiber-forming material.Also, known polybibenzoates exhibit an extremely high rate ofcrystallization, making orientation of fibers or films therefromextremely difficult and costly, if not impossible, from a commercialviewpoint. The novel homopolymer polyesters prepared from themethyl-substituted polyphenylcarboxylic acids of this invention, quiteunexpectedly in view of the experiences described above, make toughfilms and fibers with very desirable properties.

SUMMARY OF THE INVENTION

The novel compositions of matter are methyl-substituted polyphenyl acylcompounds of the formula ##STR1## wherein n is a whole number from 1 to3 inclusive, Y is selected from the class consisting of methyl and--COOR, and each R is hydrogen or a monovalent organic group of 1 to 24carbon atoms, preferably methyl, when Y is methyl each X is methyl, andwhen Y is --COOR each X is independently selected from the classconsisting of methyl and --COOR.

The monohydric alcohol esters of the methyl-substituted carboxylic acidsare plasticizers for polyvinylchloride. The diacyl compounds can bereacted with compounds capable of forming amides to form novelpolyamides for film and fiber applications. The diacyl compounds whenreacted with dihydric alcohols, such as those having two to ten carbonatoms, form novel polyesters for film and fiber applications.

DETAILED DESCRIPTION OF THE INVENTION

In general, the novel methyl-substituted polyphenylacyl compounds ofthis invention are produced by the oxidation of at least one paramethylgroup of a polymesityl compound.

The novel compositions of matter are methyl-substituted polyphenylacylcompounds of the formula ##STR2## wherein n is a whole number from 1 to3 inclusive, Y is selected from the class consisting of methyl and--COOR and R is hydrogen or a monovalent organic group of 1 to 24 carbonatoms, preferably methyl, when Y is methyl, each X is methyl and Y is--COOR, each X is independently selected from the class consisting ofmethyl and --COOR. Among the specific acids which are embodiments ofthese novel compositions of matter are2,2',4,6,6'-pentamethylbiphenyl-4'-carboxylic acid;2,2',-6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid;2-methylbiphenyl-2',4,4',6,6'-pentacarboxylic acid;2,2',2",4,4',6,6',6"-octamethyl-m-terphenyl-4"-carboxylic acid;2,2',2",4',6,6',6"-heptamethyl-m-terphenyl-4,4"-dicarboxylic acid;2,2',2",2'",4,4',4",6,6',6",6"'-undecamethyl-m-quaterphenyl-4",'-carboxylicacid;2,2',2"2"',4',4",6,6',6",6"'-decamethyl-m-quaterphenyl-4,4"'-dicarboxylicacid;2,2',2",2"',2"",4,4',4",4'",6,6',6",6'",6""-tetradecamethyl-m-quinquephenyl-4""-carboxylic acid;2,2',2",2'",2"",4',4",4"',6,6',6",6"',6""-tridecamethyl-m-quinquephenyl-4,4""-dicarboxylicacid and the methyl esters of these acids.

While the polymesitylenes useful in this invention can be produced byany technique, I have found that anodic electrochemical coupling ofpolymethylsubstituted benzenes is particularly useful. The electrolyticcoupling of polymethylbenzene to its biphenyl derivatives has beenreported by L. Eberson and K. Nyberg ("Anodic Oxidations", ACS Div. ofPet. Chem., Chicago, Vol. 15, No. 4, September 1970, B7).

The required electrolytic reactions were carried out by applying asource of direct current to two electrodes in an electrically conductingsolution of the organic compounds. Since most organic compounds arenon-conductors, acids, bases, or salts were necessary to provideelectrical conductivity. These substances must be chosen so that theirreduction or oxidation occurs with more difficulty than that of theorganic compound. For anodic processes in non-aqueous solvents it iswell-known that tetrafluoroborates, fluorophosphates, nitrates, amongothers can be used as electrolytes. It is also known that solvents whichhave sufficiently high dielectric constants to promote ionization of theelectrolyte when used alone are acetonitrile, dimethylformamide,propylene carbonate and methylene chloride. Electrolytes used with thesesolvents can be tetraalkylammonium salts or lithium salts. Since thevoltage necessary to carry out the electrolysis depends upon theresistance of the solution for non-aqueous solutions, a voltage of 100volts can be necessary under laboratory conditions to obtain a currentflow with a reasonable magnitude where resistances of 1000 ohms orhigher are present.

The yield of any oligomer can be maximized by carefully selectingprocess conditions. The electrolyte composition, cell design andtemperature variations must be controlled to permit removal of thedesired oligomer from solution before its concentration becomes toolarge. This prevents its conversion to higher oligomers if it remainsdissolved or its precipitation on the anode. Lower oligomers can beseparated and recycled to extinction.

Good yields of bimesityl and other oligomers are possible if theoligomers are removed rapidly enough. The product of the anodic couplingis a heavy solute which progressively separates out of the electrolyte.The product can be recovered by cooling the solute and electrolyte mixto -20° C. when moderate quantities have been converted. A preferablemethod of recovery is by solvent extraction when low to moderatequantities have been converted. Aliphatic hydrocarbons of a lowerboiling point than that of the product are utilized as the extractingmedium. Heptane was utilized in this instance.

A divided cell is often used in electrolyses. The cathode is separatedfrom the anode by means of a diaphragm, often porous alumina, to preventthe reduced product from being re-oxidized. In this instance, apolyethylene screen was used to electrically insulate the cathode fromthe anode and not as a diaphragm. The optimum current density varies butit is generally between 0.02 and 0.2 amp/sq. cm. The actual number ofampere-hours is normally substantially greater than the theoretical(53.6 ampere hours per mole of product, assuming two electrons permolecule of reagent) and was approximately two-times greater in the caseof bimesityl.

Separation of the bimesityl and other oligomers was by fractionaldistillation followed by a purifying distillation. The batch fractionaldistillation to obtain the crude oligomers was performed by well-knownmethods. Since these materials are high melting point solids, the entirepurifying distillation was conducted within an oven at a temperatureabove the melting point but below the boiling point of the compound.

Suitable polymesitylenes useful for producing the acids of thisinvention include 2,2',4,4',6,6'-hexamethylbiphenyl;2,2',2",4,4',4",6,6',6"-nonamethyl-m-terphenyl;2,2',2",2'",4,4',4",4"',6,6',6",6"'-dodecamethyl-m-quaterphenyl whichare, respectively, the bimesityl, the termesityl and the quatermesityl.Similarly,2,2',2",2"',2""4,4',4",4"',4"",6,6',6",6"'6""-pentadecamethyl-m-quinquephenyl,which is the quinquemesityl, the hexamesityl and the higher oligomers ofmesitylene are useful for producing the acids of this invention.

Irrespective of how the polymesitylenes are produced, at least one ofthe paramethyl (4 or 4')groups on a mesityl ring having only one directbond to another mesityl ring is oxidized with molecular oxygen (e.g. O₂gas or air) to the carboxylic acid function in liquid phase processespreferably employing acetic acid as reaction solvent.

I have found, in accordance with my invention, that newpolyphenylcarboxylic acids containing no more tha one acyl moiety on anyaromatic ring of the polyphenyl carboxylic acid can be prepared in avery convenient method by mild oxidation of the polymesitylene using acobalt catalyst. While the reaction can be carried out neat, it isgenerally preferred to use an organic solvent, preferably an organicacid, to prevent sublimination of the polymesityl. In the process onlythe methyl groups para to a biphenyl linkage are oxidized.

In this process, the polymesityl compound can be reacted with anoxygen-containing gas (oxygen, air, etc.) in the presence of cobalticions at a temperature within the range of 20° to 150° C., desirably 70°to 120° C., preferably 90° to 115° C., and at a pressure which maintainsthe organic acid (e.g. acetic acid) in the liquid phase. This generaltype of mild oxidation is described by T. Morimoto and Y. Ogata, (J.Chem. Soc. (B) 62, 1353 (1967)), which is incorporated by reference andemploys oxygen and cobaltic acetate in acetic acid solution at 90° C.Suitable organic carboxylic acids which can be used as a solvent includeacetic acid, propionic acid, etc. Approximately 0.01 to 3 parts byweight cobaltic ion per part by weight polymesityl compound can be used.In general, the higher the concentration of cobaltic ion the faster therate of oxidation. The concentration of oxygen is not critical butshould be in excess of theoretical. The time of the reaction isgenerally a function of the temperature and pressure. The higher thetemperature, the faster the reaction. The acid can be isolated byconventional means or esterified with a lower alcohol (methanol,ethanol, isoproanol, to facilitate separation and purification.

Among the specific acids which are prepared by this technique are2,2',4,6,6'-pentamethylbiphenyl-4'-carboxylic acid;2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid;2,2',2",4,4',6,6',6"-octamethyl-m-terphenyl-4"-carboxylic acid;2,2',2",4',6,6',6"-heptamethyl-m-terphenyl-4,4"-dicarboxylic acid;2,2',2",2"',4,4',4",6,6',6",6"'-undecamethyl-m-quaterphenyl-4"'-carboxylicacid;2,2',2",2"',4',4",6,6',6",6"'-decamethyl-m-quaterphenyl-4,4"'-dicarboxylicacid;2,2',2",2"',2"",4,4',4",4"',6,6',6",6"',6""-tetradecamethyl-m-qinquephenyl-4""-carboxylicacid;2,2',2",2"',2"",4',4",4"',6,6',6",6"',6""-tridecamethyl-m-quinquephenyl-4,4""-dicarboxylicacid.

In the case where it is desired to produce polyphenyl compounds havingmore than one acyl group per aromatic ring, other techniques can beemployed such as a liquid phase oxidation process using molecular oxygencatalyzed by the conjoint presence of a metal and bromine, as is taughtin U.S. Pat. No. 2,833,816 which is incorporated by reference. Thistechnique employs an acid medium, preferably acetic acid medium, and aheavy metal catalyst, preferably consisting essentially of cobalt and/ormanganese, with a source of bromine ion to enhance the catalytic effectof the metal ion. The polymesityl compound can be reacted with anoxygen-containing gas (oxygen, air, etc.) at a temperature within therange of 120° to 275° C., desirably 150° to 250° C., and preferably 170°to 225° C., and at a pressure which maintains the organic acid (aceticacid, propionic acid, etc.) in the liquid phase at such temperaturerange. The ratio of total oxygen fed into the reaction mixture relativeto the hydrocarbon can be in the range of about 2 to 500 moles of oxygenper mole of substituted hydrocarbon, desirably in the range of 5 to 300,and preferably in the range of 5 to 75. Generally the pressure can be inthe range of atmospheric up to about 1500 p.s.i.g. Among the specificacids which can be prepared by this method is2-methyl-2,2',4,4',6,6'-pentacarboxylic acid.

2,2',6,6'-Tetramethylbiphenyl-4,4'-dicarboxylates and the esters of theother acids can be produced by reacting the appropriate mono ordicarboxylic acid compound (free acid or acyl halide) with a suitablemonohydroxy compound at a temperature of 60° to 200° C. or the dimethylester can be produced first and the appropriate diester produced bytransesterification with a suitable monohydroxy compound at atemperature of 60° to 200° C.

The monohydroxy esters of polyphenyl carboxylic acids of my inventionare useful as plasticizers of polyvinylchloride and other polymerformulations. Suitable monohydric alcohols useful for producing theester include aromatic of aliphatic, straight or branched chain,substituted or unsubstituted compounds of from 1 to 24 carbon atoms.Examples are alcohols such as methyl alcohol, ethyl alcohol, propylalcohol, butyl alcohol, isobutyl alcohol, 2-ethyl hexyl alcohol, amylalcohol, hexyl alcohol, cyclohexyl alcohol, heptyl alcohol, dodecylalcohol, octyl alcohol, isotridecyl alcohol, stearyl alcohol, oleylalcohol, tetracosyl alcohol, as well as aromatic hydroxy compoundscontaining from 6 to 24 carbon atoms such as phenol, naphthol, cresol,para-stearylphenol, etc.

These esters can be produced under conventional reaction conditions byreacting from about 1 to 10 moles of monohydroxy compound per carboxylequivalent of said acid compound to form a solution of ester andmonohydroxy compound. If desired esterification catalysts ortransesterification catalysts can be used, such as sulfuric acid,phosphoric acid, paratoluene sulfonic acid, benzene sulfonic acid,stannous octoate, boron trifluoride etherate, tetraalkyl titanates andzirconates of U.S. Pat. No. 3,056,818 etc.

The esters of monohydroxy compounds containing from 1 to 4 carbon atomsin each alkyl group can be used advantageously in ester interchangeprocesses for producing high molecular weight polyesters while theesters containing from 1 to 24 carbon atoms in each ester moiety,preferably alkyl groups containing from about 4 to 13 carbon atoms, canbe used as plasticizers for resinous polymers of vinyl chloridecontaining at least 50 mole percent vinyl chloride units. The resinouspolymers of vinyl chloride include homopolymeric polyvinyl chloride,95/5 vinyl chloride/vinyl acetate copolymers, etc. The plasticizers canbe used in a concentration of from 5 to 300 parts by weight per each 100parts by weight resinous polymer of vinyl chloride as the soleplasticizer or together with other plasticizers such as dioctylphthalate, trioctyl phosphate, epoxidized glyceride oils, etc.

The polyphenyl dicarboxylic acids can be used to produce high molecularweight essentially linear condensation polymers, such as polyesters orpolyamides. These can be made by condensing at least one of the noveldiacyl compounds with an organic compound providing at least tworeactive groups derived from either a polyhydric alcohol, a polyamine, apolyisocyanate or a polyisothiocyanate. These polyols, polyamines,polyisocyanates, or polythiocyanates can be saturated or unsaturatedaromatic or aliphatic, straight or branched chain, substituted orunsubstituted.

In general, the highly polymeric essentially linear condensationpolymers are resinous polymers consisting essentially of recurring unitsof an acyl compound wherein said acyl compound comprises a polyacylradical of a methyl-substituted polyphenylcarboxylic acid of thestructural formula ##STR3## wherein n comprises a whole number from 1 to3 inclusive; L is selected from the group consisting of ##STR4## and--O-- radicals, Z is selected from the group consisting of divalentaliphatic moieties and divalent aromatic moieties, m is a number of saidrecurring units wherein the said resinous polymer has an inherentviscosity of at least 0.20 dl/g in a 60/40 phenol-tetrachloroethanesolvent at 30° C.

For purposes of this invention, the term "alkylene" is defined asincluding divalent groups having 2 to 20 carbon atoms in the alkylenechain. For purposes of this invention, the term "aromatic moiety" isdefined as including divalent aromatic radicals characterized by atleast one benzene ring, i.e., the six-carbon ring of benzene or thecondensed six-carbon rings of the other aromatic radicals such asnaphthylene, phenanthylene, anthrylene, etc. The term "aromatic moiety"is further defined as including radicals containing two benzene ringsjoined by a divalent group such as a methylene group, ether, sulfone,sulfide group, etc. Examples of these radicals are phenylene,biphenylene, diphenyleneether, diphenylenemethane, diphenylene sulfone,and diphenylenesulfide. One or more hydrogens of the aromatic nucleuscan be replaced by non-reactive radical groups such as lower alkyls,halogens and nitro radicals.

The polyesters of this invention comprise a polyhydroxy componentcomprising one or more polyhydric alcohols (diols, triols, etc.) and apolycarboxylic acid component comprising one of the polyphenyldicarboxylate components. The preferred polyesters of this invention areessentially linear and comprise units of alkylene glycols containing 2to 10 carbon atoms and polyphenyl dicarboxylate moieties. The polyestersbased on 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate have anexceptionally high Tg. For example, homopolymericpolyethylene-2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate has a Tgof about 191° C. Molding temperature is about 240° C. Homopolymerictetramethylene-2,2',6,6'-tetramethylene-4,4'-dicarboxylate has a Tg of131° C. Homopolymeric polyethylene terephthalate has a Tg of about70°-75° C. and a molding temperature of 260°-270° C. Homopolymericpolyethylene naphthalene 2,6-dicarboxylate has a Tg of 115°-125° C.

The glass transition and molding temperatures of polyesters of2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid (M₂ DA) and diolsof chain lengths of up to ten carbon atoms as well as that ofpolyethylene terephthalate and other polyesters for comparison are givenin the following table.

                  TABLE I                                                         ______________________________________                                        Thermal Properties of M.sub.2 DA and Other Polyesters                                                           Molding                                     Diacid     Diol         Tg °C.                                                                           Temp. °C.                            ______________________________________                                        2,2',6,6'-tetra-                                                                         Ethylene Glycol                                                                            191       240°                                 methylbiphenyl-                                                                          1,4-Butanediol                                                                             131       --                                          4,4'-(M.sub.2 DA)                                                                        1,6-Hexanediol                                                                             97        --                                                     1,10-Decanediol                                                                            44        --                                          Terephthalic                                                                             Ethylene Glycol                                                                            70        260-270                                                1,4-Butanediol                                                                             22        240-250                                     2,6-Naphthalene                                                                          Ethylene Glycol                                                                            115-125   --                                          ______________________________________                                    

Since wash and wear characteristics of textile produced from polyesterfiber are a function of the Tg of the fiber, it is desirable to employfibers having a Tg above 100° C. For example the Tg of the polyester ofM₂ DA and ethylene glycol is well over 100° C. The polyesters of thisinvention have a singular advantage over PET, i.e., 191° C. for theethylene M₂ DA polyester versus about 74° C., in wash and wear clothing.Truck tires have not been fabricated from polyester cords since the heatbuild up in the tires raises the temperature of the tire cord above 75°C. and the tire cord loses strength at its stretches. The lower moldingtemperature of the ethylene polyester of this invention than that ofpolyethylene terephthalate, 240° C. versus 260°-270° C., reducesfabrication heat input with resulting economic utility.

Broadly speaking, the homopolymer polyesters are prepared by reacting apolyhydric alcohol with the dicarboxylic acid or lower alkyl (preferablymethyl) ester of the dicarboxylic acid. An ester-forming derivative ofthe dicarboxylic acid may be used, i.e., an acid halide, a salt, itsanhydride and/or an ester thereof, particularly an ester of thedicarboxylic acid with a lower aliphatic alcohol or with phenol.Correspondingly, ester-forming derivatives of the polyhydric alcoholsmay be employed, i.e., a derivative of the alcohol containing functionalgroups equivalent to the hydroxyl groups in their ability to react withcarboxyl groups. Thus, an alcohol may be employed in the form of anepoxide, and/or ester of the alcohol with acetic acid or other loweraliphatic acid may be used.

In a convenient method for preparing the dihydric alcohol dicarboxylatepolyester, the dimethyl ester of the dicarboxylic acid or acids isreacted with an excess of the polyhydric alcohol, 1.1 to 2.5 moles ofpolyol per mole of ester, preferably employing about 1.5 to 2.1 moles ofpolyol per mole of ester. A typical example is the reaction of ethyleneglycol with dimethyl terephthalate. The reaction is usually carried outat atmospheric pressure but higher or lower pressure may be used ifdesired. A range is usually from 0.1 to ten atmospheres. Temperature isusually from 90° to 325° C. Following the ester interchange reaction, inwhich methanol is removed as a by-product, heating is continued at anincreased temperature to bring about polycondensation. Small amounts ofcatalysts are usually added to facilitate the reaction, manganousacetate, calcium acetate, and sodium methoxide being typical esterinterchange catalysts and antimony trioxide, dibutyltin maleate, andzinc acetate are suitable polycondensation catalysts. Litharge, sodiumhydrogen hexabutoxytitanate and the tetra-alkyl titanates, such astetra-isopropyl titanate, are examples of catalysts which may be usedfor both the ester interchange and the polycondensation steps. Normally,the polycondensation reaction is continued until a degree ofpolymerization is achieved corresponding to an inherent viscosity ofapproximately at least 0.3 dl/g in a 60/40 phenol-tetrachloroethanesolvent at 30° C.

To achieve a higher degree of polymerization, the product of thepolycondensation reaction is allowed to cool to room temperature, about20° to 25° C., forming a solid material. The solid is ground to flake,following which the flake is heated below its melting point in a streamof inert gas to achieve solid phase condensation.

The polyhydric alcohols useful for producing the polyesters of thisinvention include alkylene glycols containing from about 2-12 carbonatoms, such as ethylene glycol, 1,2-propylene glycol, 1,3-propyleneglycol, butylene glycol, hexamethylene glycol, dodecamethylene glycol,etc.; aromatic polyhydric alcohols such as hydroquinone, resorcinol,Bisphenol A, etc.; cycloaliphatic glycols such as 1,4-dimethylolcyclohexane, dimethylol cyclobutane, etc.; polyoxyalkylene glycols suchas polyoxyethylene glycols, polyoxypropylene glycols, block copolymersof polyethylene and polypropylene glycol, polytetramethylene glycols,etc.; neopentyl glycol, polyhydric alcohols having three or more hydroxygroups, such as 1,1,1-trimethylol ethane, 1,1,1-trimethyol propane,pentaerythritol, sorbitol, etc.

The essentially linear polycarbonamides of this invention can be viewedas polyphenyl dicarboxamides having arylene and/or alkylene groupsjoining the amide groups of the polymer. One or more of the alkylene orarylene groups can be joined by one or more heteroatoms ##STR5## as iscommon in this art.

Suitable alkylene groups containing 2 to 24 carbon atoms includeethylene, trimethylene, hexamethylene, octamethylene, dodecamethylene,##STR6## tetracosene, etc. Suitable arylene groups containing 6 to 24carbon atoms include paraphenylene, orthophenylene,N,N-diphenyleneamine, oxydiphenylene, etc.

The high molecular weight polyamides can be prepared by well-knownmethods. These methods include reacting a dicarboxylic acid or itsderivatives such as acid chlorides with alkylene and arylene diamines,diisocyanates, diisothiocyanates and their derivatives. For example,polyamides can be prepared from the free acid(2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid) and difunctionalnitrogen-containing compounds such as diphenylmethane-4,4'-diisocyanate,diphenylether-4,4'-diisocyanate, 4,4'-diaminodiphenylmethane,paraphenylene diamine, etc.

In somewhat greater detail, the dicarboxylic acid can be reacted with anexcess of the arylene diamine, diisocyanate, or diisothiocyanate (1.1 to2.5 moles of reactant per mole of acid, preferably about 1.5 to 2.1moles of reactant per mole of acid.) The reaction can be carried out atatmospheric pressure but higher or lower pressure can be used ifdesired. The temperature is usually from about 90° to 325° C. Smallamounts of catalyst can be added to facilitate the reaction. Normally,the reaction is continued until the desired degree of polymerization isachieved.

PREPARATORY EXAMPLE A

The starting materials, the polymethyl-substituted benzenes and theirhomologues, were prepared as is described in the following example.

The electrolysis cell consisted of a sealed glass tube two inches indiameter and 18 inches long, held vertically in a support. The tube wasequipped with a take-off sidearm to return the electrolyte to thereservoir. The tube had a glass taper joint on the top of the tube toreceive the glass input tube. The two electrode leads were inserted intothe bottom of the tube using standard taper joints. The electrolyteinput was supplied through the top of the tube. A one-half inch glassfeed tube was extended to the bottom of reactor vessel through the glassstopper which sealed the taper joint. Two platinum screen electrodes,each of approximately 275 square centimeter in surface area, insulatedfrom each other by a polyethylene screen, were connected to theelectrode leads at the bottom of the reactor. A circulating pumpsupplied electrolyte from a reservoir, 1.5-3.0 liters, to the feed tubeat 20 liters/minute.

The reservoir was charged with 1.5 liters electrolyte which was 0.1molar tetraalkylamoniumtetrafluoroborate and 2.0 molar concentration ofmesitylene in acetonitrile as the solvent. Specifically, 42 grams oftetrapropylammonium tetrafluoroborate and 360 grams of mesitylene weredissolved in acetonitrile to make 1.5 liters of final solution.

The above reaction mixture was subjected to electrolysis for seven andthree-quarters hours. Current density was approximately 0.01amperes/centimeter squared. The resulting mixture was then placed in acooler overnight and held at -20° C. The next day about 37 grams ofsolids and heavy liquids were separated. The electrolysis was repeatedwith the addition of a fresh batch of 37 grams of mesitylene to theelectrolyte. The procedure was repeated until a total of eight runs hadbeen made using two batches of electrolyte, each of which wasapproximately three liters. Current densities were up to 0.055amperes/centimeter squared. Total mesitylene used was 2,280 grams or 19moles, which received 9.35 faradays of current, or approximately 0.5faradays/mole. The batches were vacuum-stripped as made in a five-literflask to remove the acetonitrile and some unreacted mesitylene. Pottemperature was 48°-50° C. at 3.0 mm Hg. The residue was extracted threetimes with 100 ml. portions of ethyl ether. The vestigial ether wasremoved by atmospheric distillation to a pot temperature of 114° C. Thesolids and heavy liquids recovered after each run were added togetherand the total quantity vacuum distilled. Pot temperature was 106° C.,head temperature 63° C. at 3.0 mm Hg. to remove unreacted mesitylene.The bimestyl fraction was obtained from the residue with a pottemperature of135°-187° C., head temperature of 118°-152° C. at 0.9 mmHg. The termesityl fraction was obtained with a pot temperature of202°-252° C., head temperature 149°-215° C. at 0.9 mm Hg.

The yields of the fractions obtained as well as the analyses are shownin Table II. The nuclear magnetic resonance (NMR) readings reported arein parts per million (ppm) in terms of the increment (δ) from thestandard tetramethylsilane (TMS). The readings are of the chemical shiftof the hydrogen located in the positions (a) through (e). When n is 1 to4 similar readings are obtained by NMR analysis for ##STR7## equivalenthydrogen positions for termesityls, quatermesityls, and quinquemesitylsin the (a) and (e) positions. The yield of co-produced higherhomologues, after separation by distillation, is shown as decreasingwith increasing molecular weight. Current efficiency is defined as theratio×100 of actual weight to theoretical weight where theoreticalweight is the equivalent weight times faradays.

                                      TABLE II                                    __________________________________________________________________________    Electrochemical Production Of Bimesityl and Homologues                        Yields and NMR Analysis                                                                Yield Current          δ Shift From The Standard -                      Wgt.  Efficiency                                                                          M.P. B.P.  in ppm Hydrogen Position                               Grams %     °C.                                                                         °C./mmHg                                                                     a  b  c  d  e                                 __________________________________________________________________________    Bimesityl                                                                               615  55    105-107                                                                            120-140/1.0                                                                         n.a.                                                                             6.82                                                                             2.32                                                                             1.88                                                                             n.a.                              Termesityl                                                                              145  17    139-140                                                                            175-185/1.0                                                                         6.95                                                                             6.82                                                                             2.30                                                                             1.90                                                                             1.45                              Quatermesityl                                                                          >50         223-224                                                                            235-255/1.2                                                                         6.96                                                                             6.80                                                                             2.30                                                                             1.90                                                                             1.48                              Quinquemesityl                                                                         >15   18    253-260                                                                            >290/2.3                                                                            6.96                                                                             6.84                                                                             2.28                                                                             1.89                                                                             1.49                              Hexamesityl and                                                                        >50         N.D. N.D.  -- -- -- -- --                                Above                                                                         Polymer   13    2    N.D. N.D.  -- -- -- -- --                                __________________________________________________________________________     Internal Standard  Tetramethyl Silane                                         Solvent  DeuterChloroform (CDCl.sub.3)                                        All singlet peaks                                                             N.D.  Not Determined                                                          n.a.  Not Applicable                                                     

EXAMPLE I

Fifteen grams cobaltous acetate was stirred in 200 ml. of acetic acid ina 500 ml three-necked round-bottom flask equipped with a thermometer,condenser, dropping funnel, electric heating mantle and magneticstirrer. Fifteen ml. of 40 percent peracetic acid dissolved in aceticacid were added slowly to the flask from the dropping funnel. The colorof the reactants changed from red (Co⁺⁺) to green (Co⁺⁺⁺) in anexothermic reaction. Five to ten minutes after the heat of reactionsubsided, external heat was applied by the mantle to increase thetemperature to 45° C. After ten grams bimesityl were added, the droppingfunnel was replaced with a gas dispersion tube. Oxygen was introduced at0.3 SCFH, measured at 25° C. and atmospheric pressure. When the reactiontemperature reached approximately 95° C. (within range of 90-115 asindicated in Table III), current to the mantle was adjusted to maintainsuch temperature for five hours. Thereafter oxygen introduction,stirring and external heating were stopped and the mixture allowed tocool to ambient temperature. The mixture was then filtered to obtain theprecipitated solids, 2.7 grams, which were washed three times with 5 ml.of acetic acid. The filtrate was saved. The solids were then washed withconcentrated hydrochloric acid to regenerate the free carboxylic acidsfrom the 2.7 grams of precipitated solids. The regenerated acids wereapproximately 80% diacid and 20% monoacid.

The initial filtrate produced in the previous paragraph was poured intoone liter of water, the precipitate filtered out, washed with morewater, and then dissolved in 200 ml of ether. Extraction of the etherwith 5% sodium bicarbonate (NaHCO₃) followed by acidification andfiltration of the water extract yielded a fraction that was 85-90% thebiphenyl diacid. A similar extraction with 5% potassium hydroxide (KOH)then gave a fraction that was 90-95% the biphenyl mono-acid. The residueafter ether evaporation was mainly unreacted bimesityl. The amounts ofthe various acids in these fractions were composited and the resultstabulated to give the results shown in Table III. Table III listspertinent data on four runs of selective bimesityl oxidation obtained bythese methods.

                                      TABLE III                                   __________________________________________________________________________    Selective Oxidation of Bimesityl                                              and Products Obtained                                                         Reagents                                                                      10 Grams Bimesityl      % Weight of                                                       40%    Temp Starting Materials                                    Run                                                                              Co(OAc).sub.2 --4H.sub.2 O                                                             CH.sub.3 COOH                                                                        °C.                                                                         DA MA TA  Others                                      __________________________________________________________________________    1  10.1     10.0    90-104                                                                            29 45 1   4                                           2  10.0      9.9   100-105                                                                            25 48 1   3                                           3  10.0     10.1   112-114                                                                            12 46 <0.5                                                                              3                                           4  15.0     15.1    99-102                                                                            39 35 1   3                                           __________________________________________________________________________     Notes:-                                                                       DA  Diacid (2,2',6,6tetramethylbiphenyl-4,4dicarboxylic                       MA  Monoacid (2,2',4,6,6Pentamethylbiphenyl-4carboxylic                       TA  May be triacids-                                                          Others  Probably aldehydes and/or alcohols                               

Analysis of these extracted fractions by nuclear magnetic resonance(NMR) was used to identify the major components present. Esterificationgas chromatography (EGC) then indicated the quantitative percent of themajor component together with the number and concentration ofintermediates and by-products. The mass spectra of the esters from EGCalso confirmed the identification of the major component and gave goodevidence of the structure of the intermediate and by-products.

The methyl esters were prepared using a 5 liter three-necked flaskequipped with a thermometer, condenser and mechanical stirrer. Aseparatory funnel and a one-inch ten-tray fractioning column were alsoused.

The crude diacid fractions (511 gms.) were mixed with 2.75 liters ofmethanol and 700 grams of dry hydrochloric acid in the 5 literthree-necked flask and heated at reflux (70°-73° C.) for 48 hours. Thereaction mixture was cooled to room temperature and the precipitatedsolids were removed by filtration with a Buchner funnel. The precipitatewas washed twice with methanol and dried. The methanol-soluble esterswere recoverable by evaporating the methanol washings. Themethanol-washed esters, 349 grams, were dissolved in 2.8 liters of ethylether. The solution was extracted five times in the separatory funnel,once with 60 ml of a 5% solution of sodium carbonate in water, once with70 ml. of a 5% solution of sodium hydroxide in water and three timeseach with 100 ml of water. The solution was dried overnight overanhydrous calcium sulfate. The calcium sulfate was filtered out and theethyl ether stripped off using atmospheric distillation. The residue wasthen vacuum flashed to a pot temperature of 270° C. at 9-11 mm of Hg.The flashed esters were then fractionally distilled in a one-inchten-tray fractionating still to separate the diacid esters and themonoacid esters. The diacid esters were then recrystallized from benzeneand vacuum dried. Thedimethyl-2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate melted at128°-129° C.

The benzene-free diacid was recovered by heating the ester in KOHsolution, acidifying with hydrochloric acid to excess hydrogen ion. Theprecipitated diacid was recovered by filtration. A water wash followedby drying under vacuum completed the purification procedure of the2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid.

EXAMPLE II

The oxidation procedure in Example I was repeated using termesitylprepared by anodic coupling.

Ten grams cobaltous acetate were stirred in 200 ml. of acetic acid. 9.8Grams of 40% peracetic acid in acetic acid were added. After the colorof the reactants changed to green, external heat was applied. Ten gramstermesityl were added, oxygen was introduced at 0.3 SCFH. When thereaction temperature reached approximately 106° C., the temperature wasmaintained for five hours. After the mixture was cooled, filtrationyielded 0.2 grams of precipitated solids, which were not further workedup. An ether extraction of the initial filtrate which had been waterwashed was extracted with 5% sodium bicarbonate, acidified and filteredto yield a 2.1 gram fraction. This fraction analyzed by NMR was 30%monoacid (2,2',2",4,4',6,6',6"-octamethyl-m-terphenyl-4"-carboxylicacid) and 70% diacid(2,2',2",4',6,6',6"-heptamethyl-m-terphenyl-4,4"-dicarboxylic acid).

The crude acid fractions (4.8 grams) were esterified in a wellknown gaschromatography esterification procedure. Twenty ml. methanol in twentyml. pyridine containing the crude acid were heated to 100° C. for 15minutes. Forty-five ml. trimethyl phosphate were added. Temperature wasincreased to 130° C. and rose to 175° C. through heat of reaction. Afterthe mixture cooled to ambient temperature, chloroform extraction anddistillation yielded fractions identified as the mono and diacid esters.A 0.9 gram fraction was 90% monoacid ester(methyl-2,2',2",4,4',6,6',6"-octamethyl-m-terphenyl-4"-carboxylate). A1.7 gram fraction was 81% diacid ester(dimethyl-2,2',2",4',6,6',6"-heptamethyl-m-terphenyl-4,4"-dicarboxylate).Analysis was by gas chromatography.

EXAMPLE III

The oxidation procedure in Example I was repeated using quatermesitylprepared by anodic coupling.

Fifteen grams cobaltous acetate were stirred in 200 ml. of acetic acid.Fifteen grams of 40% peracetic acid in acetic acid were added. Ten gramsof quatermesityl were oxidized at a reaction temperature of 90°-93° C.for seven hours. Filtration yielded 0.2 grams of precipitated solids.Carbonate extraction of the ether extract yielded a 1.2 gram fraction. A5% potassium hydroxide extraction yielded a 5.0 gram fraction. The fivegram fraction was esterified in a gas chromatography esterificationprocedure as in Example II. The 5.0 gram esterified fraction was 45.7%monoacid ester(methyl-2,2',2",2"',4,4',4",6,6',6",6"'-undecamethyl-m-quaterphenyl-4"'-carboxylate),44.5% diacid ester(dimethyl-2,2',2",2"',4',4",6,6',6",6"'-decamethyl-m-quaterphenyl-4,4"'-dicarboxylate)and 2.3% triacid ester which was not further characterized. Analysis wasby mass spectrograph.

Table IV lists the NMR and mass spectra analyses of themethyl-substituted polyphenylcarboxylic acids of Examples I, II and III.

                                      TABLE IV                                    __________________________________________________________________________    NMR and Mass Spectra Analyses Methyl-Substituted Polyphenylcarboxylic         Acids                                                                                              NMR Analysis - δ Shift From The Standard - In                           ppm                                                                           Hydrogen Position                                        Example                                                                            Name            a   b   c   d   e   Solvent                              __________________________________________________________________________    I    2,2',4,6,6' Pentamethyl-biphenyl-                                                             n.a.                                                                              6.90                                                                              2.31                                                                              1.95                                                                              n.a.                                                                              CDCl.sub.3                                4'-carboxylic acid                                                                            n.a.                                                                              7.83                                                                              --  1.83                                                                              n.a.                                     I    2,2',6,6'-Tetramethyl-biphenyl-4,-                                                            n.a.                                                                              7.68                                                                              --  1.88                                                                              n.a.                                                                              NaOD                                      4'-dicarboxylic acid                in D.sub.2 O                         II   2,2',2",4,4',6,6',6"-Octamethyl-m-                                                            7.07                                                                              6.92                                                                              2.30                                                                              1.87                                                                              1.42                                                                              CDCl.sub.3                                terphenyl-4"-carboxylic acid                                                                  --  7.86                                                                              --  1.98                                                                              --                                       II   2,2',2",4',6,6',6"-Heptamethyl-m-                                                             7.10                                                                              7.76                                                                              --  1.88                                                                              1.40                                                                              CD.sub.3 OD                               terphenyl-4,4"-dicarboxylic acid                                                                          1.98                                         III  2,2',2",2"',4,4',4",6,6',6",6"'-                                                              6.90                                                                              7.96                                                                              2.30                                                                              1.89                                                                              1.48                                                                              CDCl.sub.3                                Undecamethyl-m-quaterphenyl-                                                                  7.84                                                                              --  --  1.94                                                                              --                                            4'"-carboxylic acid                                                                           --  --  --  2.00                                                                              --                                       __________________________________________________________________________                            Mass Spectra Analysis                                 Example                                                                            Name               Molecular Wgt.                                                                        % of Total                                    __________________________________________________________________________    III  2,2',2",2"',4',4",6,6',6",6"'-Decamethyl-                                     m-quaterphenyl-4,4'"-dicarboxylic acid                                        (Analyzed as the ester)                                                       Monoester of Quatermesityl Mono-acid                                                             518     45.7                                               Diester of Quatermesityl Di-acid                                                                 562     44.5                                               Triester of Quatermesityl Tri-acid                                                               606      2.3                                          __________________________________________________________________________     Note:-                                                                        Internal StandardTetramethyl Silane                                           Solvent  DeuteroChloroform (CDCl.sub.3) Sodium Deuteroxide (NaOD) in          Deuterium Oxide (D.sub.2 O) per DeuteroMethanol (CD.sub.3                     Lowvoltage intensities expressed as % of total ionization                

EXAMPLE IV

This example illustrates the preparation of biphenyl pentacarboxylicacid by severe oxidation of bimesityl by the method of U.S. Pat. No.2,833,816 which is incorporated by reference. Three preparations weremade.

The oxidation reactor was a suitable pressure reactor having a corrosionresistant inner surface, such as glass, ceramic, or corrosion resistantmetal as titanium or alloy, e.g., a titanium pressure vessel three feetlong and three inches in diameter equipped with means of agitation suchas gas flow through the end of the reactor or a mechanical agitatingdevice, and with means for heating the reactor contents to 225° C. orcooling rapidly to ambient temperatures the contents thereof such as acoil or jacket, reflux condenser for refluxing the solvent during thereaction, a gas inlet tube for nitrogen, a vent gas outlet for oxygenand nitrogen, a thermometer and manometer for measuring temperature andpressure.

The reaction vessel was charged with the following solvent mix for batchoxidation:

1250 ml of acetic acid containing 50 ml of water

3.96 gm cobalt acetate tetrahydrate

7.85 gm manganese acetate tetrahydrate

0.16 gm sodium bromide

0.42 ml. tetrabromoethane.

A feedstock of bimesityl, e.g. 230 gms. was introduced with the solventmix into the reaction vessel through the top of the reactor. Saidmixture was heated to 188° C. under a nitrogen gauge pressure of 250 psi(17.6 kg/sq cm) and then air was introduced into the reaction mixturethrough the bottom of the said reactor as an oxygen source and foragitation. The condenser refluxed the solvent through the oxidation.

When the oxygen content of the exhaust gas from the reactor reached 18%,the reaction was terminated by introducing nitrogen and discontinuingthe heating. The reactor and its contents were then cooled to ambienttemperature. The desired biphenyl polybasic acids were obtained in theform of a slurry in the reaction mixture. The entire reaction mixturewas decanted from the reaction vessel and filtered to remove thepoly-acid product. The acetic acid and by-product water were evaporatedfrom the filtrate in a porcelain evaporating dish on a steam bath toobtain the solids remaining in the filtrate. Table V indicates thereaction conditions and yields obtained.

                  TABLE V                                                         ______________________________________                                        Batch Oxidation of Bimesityl                                                  To Biphenyl Pentacarboxylic Acid                                              Run              (1)      (2)      (3)                                        ______________________________________                                        Feed Wgt., gms   230      225      100                                        Moles of Feed    0.97     0.94     0.44                                       Conditions                                                                    Pressure, psig   250      250      250                                        Initial Temperature, °C.                                                                193      193      193                                        Maximum Temperature, °C.                                                                215      214      210                                        Average Temperature, °C.                                                                213      213      204                                        Run Time, Minutes                                                                               78      53.sup.(3)                                                                              30                                        Wgt. % Metals (On Solvent)                                                                     0.3      0.3      0.1                                        Solvent/Feed, Wgt.                                                                             6        6        8                                          Atom Ratio - Co:Mn:Br.                                                                         1:2:3    1:2:3    1:2:3                                      Moles % O.sub.2 Absorbed                                                                        85       85      118                                        Moles CO.sub.2 Produced                                                                        1.5      1.5      1.1                                        Yields                                                                        Wgt % Cake.sup.(1)                                                                              64       65       45                                        Wgt % Filtrate Solids.sup.(2)                                                                  134      149      141                                        Analysis                                                                      Cake Acid Number 700      726      Not De-                                    (Theoretical 814)                  termined                                   ______________________________________                                         .sup.(1) Theory is 414/238 = 174 Wgt %                                        .sup.(2) Contained acetic acid                                                .sup.(3) Air rate was 1/3 faster in Run (2) than Run (1).                

The 2-methylbiphenyl-2,4,4',6,6'-pentacarboxylic acid was isolated fromthe reaction mixture by esterification and fractionation and analyzedusing nuclear magnetic resonance (NMR). Among the other products presentand isolated was the hexamethyl ester of the hexacarboxylic acid.

                  TABLE VI                                                        ______________________________________                                        NMR Analysis - Biphenyl Pentacarboxylic Acid                                                 δ Shift from the Standard                                               Hydrogen Position                                              Example Name         b        d      Solvent                                  ______________________________________                                        IV      2-Methylbiphenyl                                                                           8.02     1.92   CDCl.sub.3                                       2',4,4',6,6' penta-                                                                        8.51     --                                                      carboxylic Acid                                                                            8.70     --                                              ______________________________________                                         Note:                                                                         Internal Standard  Tetramethyl Silane                                         Solvent  DeuteroChloroform (CDCl.sub.3)                                  

EXAMPLE V

This example illustrates the production of high molecular weightpolyamides and conversion into polyamide films suitable forhigh-temperature electrical insulation, typically having high dielectricconstants.

One and one-half grams 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylicacid was dissolved in 5.8 grams of N-methyl-2-pyrrolidone in a smallround-bottomed three-necked flask equipped with a thermometer, electricheating mantle and magnetic stirrer. The solution was heated to150°-170° C. with stirring. Over a period of 45 minutes, 1.25 grams ofdiphenylmethane-4,4'-diisocyanate was added while maintaining thetemperature at 150°-170° C. with stirring. Carbon dioxide was evolved.The temperature of 170° C. was maintained for an additional hour afterwhich an additional 0.25 grams of diphenyl methane 4,4' diisocyanatewere added. Heating and stirring were continued for another 30 minutesat 170° C. The solution was then diluted with 3.0 grams ofN-methylpyrrolidone to reduce the viscosity to Z5-Z6 (Gardener-Holdt) at20% solids. A second dilution with 3.0 grams of N-methylpyrrolidone wasthen made to reduce solids to 15%. A clear solution with viscosity of 40Stokes resulted.

The inherent viscosity of the polyamide was determined using aCannon-Fensky viscosimeter. The inherent viscosity was measured at 25°C. at a concentration of 0.5% by weight of the polymer in dimethylacetamide.

A film was then cast from a 15% weight solution upon glass plate andcured with heat. The Massachusetts Institute of Technology (MIT) filmfolding endurance test was used to measure film toughness.

EXAMPLE VI

Example V was repeated using 1.5 grams2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid and 1.75 gramsdiphenylether 4,4'-diisocyanate in place of the diphenylmethanediisocyanate (the same mole ratio of reactants). Solvent was added toadjust the resultant polymer solution to 15% weight solids with aviscosity greater than Z6 (Gardner-Holdt) and equal to 148 Stokes.Inherent viscosity was determined at 0.5% weight and cast film toughnessdetermined.

EXAMPLE VII

This example illustrates the production of a polyamide from2,2',6,6'-tetramethylbiphenyl-4,4'-diacyl chloride and a diamine. Thediacid chloride derivative was prepared by refluxing overnight 2.0 gmsof the diacid in 20 ml. of thionyl chloride with one drop ofN,N-dimethylformamide as catalyst. Excess thionyl chloride wasevaporated. The resulting crystalline residue was dried in a moderatevacuum at 50° C. for two days. The melting point was 197°-200° C.

The polyamide was prepared by reacting 2.2 gms of the diacid chloridederivative with 1.30 gms of methylene bisaniline in 15 gm ofN,N-dimethyl acetamide (DMAC) as the solvent, at ambient temperature andpressure. The solvent mix was heated to 45°-50° C. for 45 minutes andthen cooled to ambient temperature over a period of two hours. A clearviscous solution, viscosity 80 Stokes and 16% weight solids(calculated), resulted. DMAC was added to thin the polymer solution.Water was then added to precipitate the polymer which was separated byfiltration. The crumbly granules of precipitated polymer werewater-washed and dried overnight in a vacuum oven. The inherentviscosity at 0.5% weight concentration was determined. Cast filmtoughness was measured.

Product characterizations as to the films by the processes of Examples Vto VII are summarized in Table VII.

                  TABLE VII                                                       ______________________________________                                        Polyamides From 2,2',6,6' Tetramethyl-                                        4,4'-Dicarboxylic Acid                                                               Inherent   Solution  Film Folding                                      Example                                                                              Viscosity.sup.(1)                                                                        Viscosity.sup.(2)                                                                       Endurance.sup.(3)                                 ______________________________________                                        V      0.90        40       6500-10,000 (1.2 Mils)                            VI     1.08       150       300 (1.3 Mils)                                    VII    0.86       --         15-50,000 (0.9 Mils)                             ______________________________________                                         .sup.(1) 0.5% in DMAC (N,Ndimethyl acetamide)                                 .sup.(2) 15% solids in NMP (Nmethyl-2-pyrrolidone)                            .sup.(3) MIT Folding Endurance (Double Folds)                            

EXAMPLE VIII

This example illustrates the production of a high molecular weighthomopolymeric polyethylene2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate by ester interchange ofthe dimethyl ester with ethylene glycol in melt followed by solid statepolymerization.

Five grams of dimethyl 2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate,2.1 grams of ethylene glycol and 0.1 grams of dibutyl tin maleate wereheated a 180°-185° C. in a test tube equipped with a nitrogen bubblerand a side-arm. During the heating, nitrogen was slowly bubbled throughthe mixture. After the mixture was heated for two hours, the nitrogenflow was discontinued. A partial vacuum was pulled on the mixture over aperiod of 10 to 15 minutes, using a vacuum pump attached to theside-arm, and when the temperature rose to 260° C. a full vacuum (0.2 mmHg) was applied and held for two hours. Inherent viscosity of theproduct was 0.21 deciliters per gram (dl/g), measured at a concentrationof 0.4 grams per deciliter in a 60:40 by weight mixture of phenol andsymmetrical tetrachloroethane.

The above product was ground to #10 mesh and heated in a test tube at200°-210° C. and 0.05 mm Hg vacuum for 32 hours. After 16 hours, thewhite homopolymeric ethylene2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate had an inherentviscosity of 0.59 dl/g. After the second 16 hours, the inherentviscosity was 0.84 dl/g.

EXAMPLE IX

This example illustrates melt polymerization to a relatively high I.V.One hundred twenty grams dimethyl2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate, 45.6 grams of ethyleneglycol, 0.1 grams of dibutyl tin maleate, 0.05 grams of calcium acetateand 0.5 ml. of antimony trisbutoxide were heated to 200° C. for twohours in a round bottom flask equipped with a mechanical stirrer and twoside-arms. Nitrogen was bubbled slowly through the mixture during theperiod of heating with stirring. After two hours a partial vacuum waspulled on the mixture for 10 to 15 minutes, using a vacuum pump attachedto the side-arm. When the temperature rose to 260° C., a full vacuum(0.1-2.2 mm Hg) was applied with continued stirring and kept for 8.0hours. Inherent viscosity of the light brown homopolymer was 0.87 dl/gmeasured as described earlier. Strong fibers could be pulled from themelt.

Polymerization data with several diols are in Table VIII.

                                      TABLE VIII                                  __________________________________________________________________________    Polymerization Data                                                                    Diol                                                                              M.sub.2 DMe Reaction        Melt                                                                              Polymer                                   Weight                                                                            Weight                                                                             Polymeriza-                                                                          Time    Catalyst                                                                              I.V.                                                                              I.V.                             Diol     Grams                                                                             Grams                                                                              tion   Hrs/°C./mmHg                                                                   Amount  (dl/g)                                                                            (dl/g)                                                                             Tg °C.               __________________________________________________________________________    Ethylene Glycol   Solid State                                                                          16/200- None    0.18                                                                              --   --                                                   210°10.1                                                                       (Control)                                    Ethylene Glycol                                                                        2.1 5.0  Melt   2/260/0.2                                                                             Sb/0.1 g    0.27 184                         Ethylene Glycol   Solid State                                                                          16/200- Sb*     0.30                                                                              0.64 191                                                  210°/0.1                                      Ethylene Glycol   Solid State                                                                          16/200- Sn*     0.21                                                                              0.59                                                      210/0.1                                              Ethylene Glycol   Solid State                                                                          32/200- Sn*     0.21                                                                              0.84                                                      210/0.1                                              1,4-Butanediol                                                                         2.7 4.5  Melt   2/260/0.2                                                                             Ti/0.05 ml  0.37 131                         1,6-Hexanediol                                                                         3.6 4.5  Melt   2/260/0.2                                                                             Ti/0.05 ml  0.31  97                         1,10-Decanediol                                                                        3.8 4.1  Melt   2/260/0.2                                                                              ##STR8##   0.95  44                         __________________________________________________________________________     Sb  Antimony trisbutoxide                                                     Sn  Dibutyl Tin Maleate                                                       Ti  Tetran-butyl titanate                                                     M.sub.2 DMe  Dimethyltetramethylbiphenyldicarboxylate                         *Additional catalyst not utilized                                        

EXAMPLE X

This example illustrates compression molding of a polyester film of thisinvention. Homopolymeric polyethylene2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylate (PEM₂) having an I.V.of 0.87 dl/g was dried at 120° C. and 635 mm (30 inches) Hg overnightand placed between aluminum sheets and spacers to obtain the desiredthickness. The polyester was placed in a press at 240° C. and held underpressure for five minutes. The sample was then removed from the pressand allowed to cool without pressure. A fiberglass blanket was used tocover the sample in order to slow the cooling rate. Using thisprocedure, a 0.87 dl/g polyester powder was molded to give a film with a0.77 dl/g inherent viscosity. The inherent viscosity loss wasapproximately the same as would be observed for poly(ethyleneterephthalate). For compression molding of thicker parts up to 125 mils,a ten minute heating time was employed with a picture frame mold insteadof aluminum sheets.

Physical properties of the film and shaped molded parts made accordingto the above procedure are given in the following Table IX.

                  TABLE IX                                                        ______________________________________                                        Properties of PEM.sub.2 Film and Molded Parts                                 ______________________________________                                        Density, g/cm.sup.3           1.14                                            Glass Transition Temperature,                                                                    °C. DTA                                                                           191                                                                Rheovibron 227                                             Heat Deflection Temperature, °C., 264 psi                                                        172                                                 Ultimate Tensile Strength, psi                                                                          7658                                                Elongation at Break, %    4.1                                                 Flexural Modulus, psi     282,000                                             Young's Modulus dyne/cm.sup.2                                                                           1 × 10.sup.10                                 Tensile Impact Strength, psi                                                                            41                                                  Limiting Oxygen Index, % O.sub.2                                                                        27-27.5                                             ______________________________________                                    

What is claimed is:
 1. A methyl-substituted polyphenyl compound of thestructural formula ##STR9## wherein n is a whole number from 2 to 3inclusive, Y is selected from the class consisting of methyl acylhalideand --COOR, R is hydrogen or a monovalent alkyl group of 1 to 24 carbonatoms, when Y is methyl, each X is methyl and when Y is --COOR, each Xis selected from the class consisting of methyl and --COOR.
 2. Thecompound of claim 1 wherein Y is methyl.
 3. The compound of claim 1wherein Y comprises a --COOR group and X comprises methyl groups.
 4. Thecompound of claim 1 wherein X and Y comprise --COOR groups.
 5. Thecompound of claim 1 wherein said R comprises methyl groups.
 6. Thecompound of claim 2 which comprises2,2',2",4,4',6,6',6"-octamethyl-m-terphenyl-4"-acyl compounds.
 7. Thecompound of claim 2 which comprises2,2',2",2"',4,4',4",6,6',6",6"'-undecamethyl-m-quaterphenyl-4"'-acylcompound.
 8. The compound of claim 3 which comprises2,2',2",4',6,6',6"-heptamethyl-m-terphenyl-4,4'-diacyl compound.
 9. Thecompound of claim 3 which comprises2,2',2",2"',4',4",6,6',6",6"'-decamethyl-m-quaterphenyl-4,4"'diacylcompound.
 10. A process for producing methyl-substituted polyphenylcompounds of the structural formula ##STR10## wherein n is a wholenumber from 1 to 3, Y is selected from the class consisting of methylgroups acylhalide and -COOH, which comprises oxidizing at least one paramethyl group of a polymesityl wherein said process is carried out usingcobaltic catalyst at a temperature within the range of from 20° to 150°in acetic acid medium.
 11. A resinous polymer of a methyl-substitutedpolyphenylcarboxylic acid compound wherein the said polymer has thestructural formula ##STR11## wherein n comprises a whole number from 1to 3 inclusive, L is ##STR12## Z is selected from the group consistingof divalent aliphatic moieties and divalent aromatic moieties, m is anumber of recurring units wherein the said resinous polymer has aninherent viscosity of at least 0.20 dl/g in a 60/40phenol-tetrachloroethane solvent at 30° C.
 12. The polymer of claim 11wherein the said divalent aliphatic moiety comprises an alkylene grouphaving 2 to 20 carbon atoms in the alkylene chain.
 13. The polymer ofclaim 11 wherein said divalent aromatic moieties are selected from thegroup consisting of phenylene, biphenylene, diphenylene ether,diphenylenemethane, diphenylenesulfone, diphenylenesulfide, naphthylene,phenanthrylene and anthrylene moieties.
 14. The polymer of claim 13wherein said aromatic moieties comprise substituted moieties, saidsubstitutions selected from the group of radicals consisting of loweralkyls, halogens, and nitro radicals.
 15. The polymer of claim 11wherein the said acid comprises2,2',6,6'-tetramethylbiphenyl-4,4'-dicarboxylic acid.
 16. The polymer ofclaim 15 wherein Z comprises ethylene.
 17. The polymer of claim 15wherein Z comprises butylene.
 18. The polymer of claim 15 wherein LZL is##STR13##
 19. The polymer of claim 15 wherein LZL is ##STR14##
 20. Theresinous polymer of claim 11 wherein the said polymer comprises apolyamide of a methyl-substituted polyphenylcarboxylic acid compound anda compound selected from the group consisting of a polyamine, apolyisocyanate and a polyisothiocyanate.